The Guadiana Valley Natural Park is a protected area, with an area of 69700 hectares, located in the southeast of the Portuguese territory, in the Alentejo region.

The park includes the municipalities of Mértola and Serpa, located district of Beja, covering the waterfront of the Guadiana River and the Mértola village, town of great historical interest.

The Guadiana Valley Natural Park was created to protect part of the Guadiana river section and the surrounding plain, is one of the driest areas of the country, with an average annual rainfall of 600 mm. The south, between Castro Marim and Vila Real de Santo António, lies one marsh area, which acts as a “nursery” for juvenile fish and an important refuge for many species of birds.